Systems and methods for providing dynamic vacuum pressure in an articulated arm end effector

ABSTRACT

A system is disclosed for providing dynamic vacuum control to an end effector of an articulated arm. The system includes a first vacuum source for providing a first vacuum pressure with a first maximum air flow rate, and a second vacuum source for providing a second vacuum pressure with a second maximum air flow rate, wherein the second vacuum pressure is higher than the first vacuum pressure and wherein the second maximum air flow rate is greater than the first maximum air flow rate.

PRIORITY

The present application claims priority to U.S. patent application Ser.No. 16/047,713 filed Jul. 27, 2018, which claims priority to U.S. patentapplication Ser. No. 15/259,939 filed Sep. 8, 2016, which claimspriority to U.S. Provisional Patent Application Ser. No. 62/215,489filed Sep. 8, 2015 and U.S. Provisional Patent Application Ser. No.62/262,136 filed Dec. 2, 2015, the disclosures of which are herebyincorporated by reference in their entireties.

BACKGROUND

The invention generally relates to robotic systems, and relates inparticular to robotic systems having an articulated arm with an endeffector that employs vacuum pressure to engage objects in theenvironment.

Most vacuum grippers employ vacuum pressures well below 50% ofatmospheric pressure, and are referred to herein as high vacuum. Atypical source for a high vacuum gripper is a Venturi ejector, whichproduces high vacuum but low maximum air flow. Because of the low flow,it is essential to get a good seal between a vacuum gripper and anobject, and it is also important to minimize the volume to be evacuated.

Suppliers of ejectors and related system components include VacconCompany, Inc. of Medway, Mass., Festo US Corporation of Hauppauge, N.Y.,Schmalz, Inc. of Raleigh, N.C. and others. In some instances where agood seal is not possible, some systems use high flow devices. Typicalhigh flow devices are air amplifiers and blowers, which produce thedesired flows, but cannot produce the high vacuum of a high vacuumsource. High flow sources include the side-channel blowers supplied byElmo Rietschle of Gardner, Denver, Inc. of Quincy, Ill., Fuji ElectricCorporation of America of Edison, N.J., and Schmalz, Inc. of Raleigh,N.C. It is also possible to use air amplifiers as supplied by EDCO USAof Fenton, Mo. and EXAIR Corporation of Cincinnati, Ohio Multistageejectors are also known to be used to evacuate a large volume morequickly, wherein each stage provides higher levels of flow but lowerlevels of vacuum.

Despite the variety of vacuum systems, however, there remains a need foran end effector in a robotic system that is able to accommodate a widevariety of applications involving engaging a variety of types of items.There is further a need for an end effector that is able to provide highflow vacuum using a gripper that is able to handle a wide variety ofobjects.

SUMMARY

In accordance with an embodiment, the invention provides a system forproviding dynamic vacuum control to an end effector of an articulatedarm. The system includes a first vacuum source for providing a firstvacuum pressure with a first maximum air flow rate, and a second vacuumsource for providing a second vacuum pressure with a second maximum airflow rate. The second vacuum pressure is higher than the first vacuumpressure and the second maximum air flow rate is greater than the firstmaximum air flow rate.

In accordance with another embodiment, the invention provides a methodof providing a dynamic vacuum source for an end effector. The methodincludes the steps of providing at the end effector a first vacuumhaving first vacuum pressure and a first vacuum flow, and switching thedynamic vacuum source to provide at the end effector a second vacuumhaving a second vacuum pressure and a second vacuum flow. The secondvacuum pressure is higher than the first vacuum pressure, and the secondvacuum flow is greater than the first vacuum flow.

In accordance with a further embodiment, the invention provides a systemfor providing vacuum control to an end effector of an articulated arm.The system includes a vacuum source for providing a vacuum pressure at aflow rate to the end effector, and the end effector includes a coverthat includes an opening that varies significantly in radius from acenter of the cover.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description may be further understood with reference tothe accompanying drawings in which:

FIG. 1 shows an illustrative block diagrammatic view of a system inaccordance with an embodiment of the present invention;

FIG. 2 shows an illustrative diagrammatic view of an example of a systemof FIG. 1;

FIG. 3 shows an illustrative diagrammatic view of a system in accordancewith another embodiment of the present invention;

FIG. 4 shows an illustrative diagrammatic view of a system in accordancewith an embodiment of the present invention employing a high vacuumsource;

FIG. 5 shows an illustrative diagrammatic view of a system in accordancewith another embodiment of the present invention employing a high flowsource;

FIG. 6 shows an illustrative diagrammatic view of a detection systemtogether with an end effector of a system of an embodiment of thepresent invention;

FIGS. 7A and 7B show an illustrative flowchart showing a process inaccordance with an embodiment of the present invention;

FIGS. 8A and 8B show illustrative diagrammatic views of an end effectorcover for use in a system of an embodiment of the present invention;

FIG. 9 shows an illustrative diagrammatic view of an end effector of anembodiment of the invention engaging an object;

FIGS. 10A-10D show illustrative diagrammatic views of other covers foruse with end effectors of systems of further embodiments of the presentinvention;

FIGS. 11A and 11B show illustrative diagrammatic views of an endeffector in a system of an embodiment of the present invention engaginga relatively light object;

FIGS. 12A and 12B show illustrative diagrammatic views of an endeffector in a system of an embodiment of the present invention engaginga relatively heavy object; and

FIGS. 13A and 13B show illustrative diagrammatic views of an endeffector in a system of an embodiment of the present invention engagingan object that presents an unbalanced load;

The drawings are shown for illustrative purposes only.

DETAILED DESCRIPTION

In accordance with an embodiment, the invention provides a hybrid highflow/high vacuum gripper that can grip a broader set of objects thangrippers based on either high flow or high vacuum alone. Previousdesigns are usually designed for a particular object. When a good sealbetween vacuum cup and object is possible, a high vacuum device such asa Venturi ejector is typically employed. When a good seal is notpossible because of object surface irregularities or porosity, a highflow device such as a regenerative blower is typically employed. Thehybrid gripper of an embodiment of the invention, uses either highvacuum or high flow, selected in real time to provide the most effectivegrip for the object, object pose, and surrounding context.

In various embodiments, therefore, the invention provides a grippersystem that combines multiple sources of vacuum, and selecting thesource in real time. The invention provides, in an embodiment, a grippersystem that switches from a high flow source to a high vacuum source asthe pressure drops below the level sustainable by the high flow source,and a gripper system comprising a high flow source with a multistageejector, so that the non-return valve integrated in the multistageejector provides a selection mechanism in accordance with furtherembodiments.

A general approach to a vacuum gripper design, is to characterize theobject in question and select the catalog gripper, vacuum source, andother components best suited to the object. Many device suppliers andintegrators offer application engineering services to assist inselection of proper components. These options are exercised at systemdesign time however, and result in a system committed to grasp aspecific object, or in some instances a few objects.

There are numerous applications for a gripping system that could handlea broad variety of objects, varying in size, weight, and surfaceproperties. The invention provides an approach to address this need byintroducing a mechanism to select between a high flow source and a highvacuum source, depending on the present situation.

FIG. 1, for example, shows a system 10 in accordance with an embodimentof the present invention in which a high vacuum source 12 is provided aswell as a high flow source 14 and a release source 16 that are eachcoupled to a selection unit 18, that is coupled to an end effector 20.The selection unit 18 selects between the high vacuum source 12, thehigh flow source 14 and the release source 16 for providing any of highvacuum, vacuum with high flow, or a release flow to the end effector.FIG. 1 therefore shows a general form of the invention, comprisingmechanisms for producing high vacuum and high flow, a release sourceproviding either atmospheric pressure via a vent or high pressure (blowoff) via a compressor or reservoir, and a mechanism for selecting thesource best suited to the present situation.

In accordance with certain embodiments, therefore, the inventionprovides a system for providing dynamic vacuum control to an endeffector of an articulated arm. The system includes a first vacuumsource for providing a first vacuum pressure with a first maximum airflow rate, and a second vacuum source for providing a second vacuumpressure with a second maximum air flow rate, wherein the second vacuumpressure is higher than the first vacuum pressure and wherein the secondmaximum air flow rate is greater than the first maximum air flow rate.The flow rates are characterized as maximum air flow rates because, whenan object is engaged at an end effector, the flow rate may dropsignificantly.

In other embodiments, the invention provides a method for providing avacuum at an end effector on an articulated arm. The method includes thesteps of providing a first vacuum at the end effector at a first vacuumpressure with a first maximum air flow rate, and changing the vacuum atthe end effector to a second vacuum with a second vacuum pressure and asecond maximum air flow rate.

The selection mechanism may include a set of pneumatic valves driven byan estimated task state, based for example, in part, on sensor inputinformation. The selection mechanism may also select a vent or blow-offsource to release a part. In certain cases, the selection mechanism maybe based in part on a non-return valve (see FIG. 2), in other cases, anon-return valve integrated in a multistage ejector, with an additionalvalve to select a vent or blow-off source in order to release a part(see FIG. 3).

In particular, FIG. 2 shows a system in accordance with an embodiment ofthe invention that includes a compressor 30 that is coupled to anejector 32 to provide a high vacuum source that is coupled to a solenoidvalve 34. A blower 36 is also coupled to the solenoid valve 34 via anon-return valve 38, and the blower 36 provides a vacuum source with ahigh maximum flow rate. A vent or blow-off source is also provided tothe solenoid valve 34, the output of which is provided to an endeffector 40. The system therefore, provides the ejector 32 as the highvacuum source, the regenerative blower 36 as the high flow source, thenon-return valve 38 as a passive selection mechanism, and the solenoidvalve 34 connecting the effector to the release source, either vent orblow-off.

The vacuum pressure provided by the ejector 32 may be, for example, atleast about 90,000 Pascals below atmospheric and the vacuum pressureprovided by the blower 36 may be only no more than about 25,000 Pascalsbelow atmospheric, and no more than about 50,000 Pascals belowatmospheric in further embodiments. The vacuum pressure provided by theblower 36 is therefore higher than the vacuum pressure provided by theejector 32. The maximum air flow rate of the ejector may be, forexample, no more than about 5 cubic feet per minute (e.g., 1-2 cubicfeet per minute), and the maximum air flow rate of the blower may be,for example at least about 100 cubic feet per minute (e.g., 130-140cubic feet per minute).

FIG. 3, for example, shows another embodiment of the invention thatincludes a multi-stage ejector 50, a compressor 52 and a blower 54. Themulti-stage ejector 50 provides a dynamic vacuum pressure to a solenoidvalve 56 that may switch between providing an end effector 58 witheither the dynamic vacuum pressure and a vent or blow-off positive airpressure source. The system uses the non-return valve of a multi-stageejector as the selection mechanism. In particular, the multi-stageejector includes a series of apertures of increasing size (e.g., left toright as illustrated in FIG. 3). At first, the largest aperture isdominant, evacuating air quickly until the air pressure drops, then thenext size aperture become dominant until air pressure drops further, andfinally the smallest size aperture becomes dominant. The system of FIG.3, however, includes check valves on the larger aperture paths as wellas the blower 54 to keep the air flow path from defeating the highvacuum, smallest aperture, in the event of a good seal.

For example, with reference to FIG. 4, if a good seal is formed betweenan end effector 60 on an articulated arm 64 (which may for example, be atubular or conical shaped bellows) and an object 62, then the vacuumpressure provided by the smaller aperture in the multi-stage ejector 50remains dominant because the non-return valves in the multi-stageejector 50 prevent air flow backwards through the blower 54. This willprovide that the grasp of object 62 will be maintained by the lowerpressure vacuum with a lower maximum air flow rate.

With reference to FIG. 5, if a good seal is not formed between an endeffector 70 and an irregularly shaped object 72 on an articulated arm74, then the blower 54 will dominate maintaining a high flow, thereforemaintaining a grasp of object 72 with a higher maximum air flow rate.

With reference to FIG. 6, in accordance with a further embodiment, thesystem may include an articulated arm 80 to which is attached an endeffector 82, again, which may be a tubular or conical shaped bellows.The end effector 82 also includes a sensor that includes an attachmentband 86 on the bellows, as well as a bracket 88 attached to magneticfield sensor 84, and a magnet 92 is mounted on the articulated arm 80.The bellows moves in any of three directions, e.g., toward and away fromthe articulated arm as shown diagrammatically at A, in directionstransverse to the direction A as shown at B, and directions partiallytransverse to the direction A as shown at C. The magnetic field sensor84 may communicate (e.g., wirelessly) with a controller 90, which mayalso communicate with a flow monitor 94 to determine whether a high flowgrasp of an object is sufficient for continued grasp and transport asdiscussed further below. In certain embodiments, for example, the systemmay return the object if the air flow is insufficient to carry the load,or may increase the air flow to safely maintain the load.

FIGS. 7A and 7B show the process steps of a system in accordance with anembodiment of the present invention, wherein the process begins (step1000) by applying a high flow/low vacuum source to an end effector (step1002). The end effector is then applied to an object to be moved (step1004). Generally, the system begins and continues lifting the objectuntil the end of the lifting routine (step 1006), begins and continuesmoving the object until the end of the moving routine (step 1008), thenapplies a positive air pressure force to urge the object from the endeffector (step 1010) and then ends (step 1012). If the air flow at theend effector at any points falls too low, then the system mayautomatically switch to a high vacuum/low flow source as discussedabove. In certain embodiments, sensor(s) may be employed to eitherconfirm that such a switch is needed and/or has been made. In furtherembodiments, the sensor output(s) may drive a mechanical switch tochange vacuum sources.

For example, FIG. 7B also shows that once the end effector is applied toan object (step 1004), a subroutine is a called (at A to B) that firstreads the one or more sensors (step 1014). If any of the one or moresensor output(s) is outside of a threshold (step 1016), then the systemmay confirm that the system has switched to a high vacuum/low flowsource (step 1018). As noted above, in certain embodiments, the sensoroutput(s) may drive a mechanical switch that changes the vacuum at theend effector to be a high vacuum/low flow source (step 1018). The systemthen returns to the step from which it was called. During execution ofthe beginning and continuing lifting until end (step 1006), the systemcontinuously calls the subroutine (A to B) until the object is fullylifted. The system then moves to the step of beginning and continuingmoving the object until end (step 1008), and during execution of thisaction, the system continuously calls the subroutine (A to B) until theobject is fully moved.

The system may therefore, automatically switch between high flow/lowvacuum and low flow/high vacuum sources. In certain embodiments, thesystem may employ sensors to monitor and confirm that such switching isneeded and is performed. As noted, the system may also effect theswitching responsive to the one or more sensor output(s).

During low vacuum/high flow use, a specialized end effector may be usedthat provides improved grasping of long narrow objects. Certain grippersthat are designed for high flow use to acquire and hold an objectgenerally require large apertures in order to obtain an air flow ratethat is high enough to be useful for object acquisition. One drawback ofsome such grippers in certain applications, is that the object to beacquired may be small, not so small that each of its dimensions issmaller than the high flow opening, but small enough that certain of anobject's dimensions is smaller than the opening. For example, longnarrow objects such as pens, pencils etc., do not occlude enough of thehigh flow opening to generate sufficient negative forces to hold theobject securely.

In accordance with an embodiment, the invention provides a specializedcover for use with a high flow vacuum gripper. In particular and asshown in FIGS. 8A (articulated arm facing side) and 8B (object facingside), such a cover 100 may include a proximal back side 102 that doesnot permit air to flow through the material, and distal front side 104for engaging objects that is formed of a foam material. Slit openings106 in form of a star or asterisk shape are provided through thematerial in this example. During use, elongated objects may be receivedalong opposing slit openings and held by the foam material.

FIG. 9, for example, shows an elongated object 96 being held against thefoam material 104 of a cover 100 that is coupled to the end effector 82.While the elongated object 96 covers some of the opening provided by theslits 106, other portions 108 of the opening provided by the slits 106remain open. The pattern cut into the material allows for enough area tostill obtain a relatively high flow, while providing a number orpositions (or orientations) for a long, thin object to block (and thusbe held by) a sufficiently high percentage of the air flow.

The compliant foam on the surface 104 contacts the object to beacquired, giving the gripper some compliance while also acting to sealthe aperture around the object as the foam is compressed and the highflow vacuum is applied. The aperture cover therefore allows a high flowgripper to effectively pick up long narrow objects with an easy toattach cover that may be held in a tool changer and added or removedfrom the gripper autonomously during real-time operation.

In accordance with various embodiments, the cover 100 may be applied tothe end effector by a human worker into a friction fitting on the end ofthe end effector, or in certain embodiments, the cover may be providedin a bank of available end effector attachments that the articulated armmay be programmed to engage as needed, and disengage when finished,e.g., using forced positive air pressure and/or a grasping device thatsecures the end effector attachment for release from the articulatedarm.

A system is therefore provided in an embodiment, for providing vacuumcontrol to an end effector of an articulated arm, where the systemincludes a vacuum source for providing a vacuum pressure at a high flowrate to the end effector, and the end effector includes a cover thatincludes an opening that varies significantly in radius from a center ofthe cover. The opening may include finger openings that extend radiallyfrom the center of the opening. The opening may be generally star shapedor asterisk shaped. The cover may include compliant foam on a distalside of the cover that engages an object to be grasped, and an air flowresistant material on a proximal side of the cover. The vacuum pressuremay be no more than about 50,000 Pascals below atmospheric, and the airflow rate may be at least about 100 cubic feet per minute.

Covers with other types of openings are shown in FIG. 10A-10D. FIG. 10A,for example, shows a cover 120 that includes slit openings 122. FIG. 10Bshows a cover 130 that includes different sized square openings 132,134. Cover 140 shown in FIG. 10C includes small circular openings 142,and cover 150 shown in FIG. 10D includes differently shaped openings 152and 154. In each of the covers 100, 120, 130, 140 and 150, a compliantfoam surface may face the object to be acquired, and more area of thecover is provided to be open closer to the center of the cover withrespect to the outer periphery of each cover. For example, in the cover100, the center of the asterisk shape is most open. In the cover 120,the larger slits are provided in the center. In the cover 130, thelarger square openings are provided in the center. In the cover 140, thegreater concentration of the circular openings is provided in thecenter, and in the cover 150, the larger shape 154 is provided in thecenter.

Systems in accordance with certain embodiments of the invention are ableto monitor flow within the end effector as well as the weight andbalance of an object being grasped. FIGS. 11A and 11B show an object 160being lifted from a surface 162 by the end effector 82 that includes theload detection device of FIG. 6. The high flow/low vacuum source isinitially applied. Upon engaging the object 160, the system notes theposition of the detection device and the level of flow (F₁) within theend effector as well as the vacuum pressure (P₁) and load (W₁) as shownin FIG. 11A. Once the object 160 is lifted (FIG. 11B), the system notesthe change in the amount of flow (ΔF₁). In this example, the loadprovided by the object 160 is relatively light (ΔW₁), and a smallvariation (ΔF₁) in flow may (when considering the load and aperturesize) may be accepted, permitting the source to remain high flow/lowvacuum. FIGS. 12A and 12B, however, show the end effector lifting aheavy object with a more flat surface.

FIGS. 12A and 12B show an object 170 being lifted from a surface 172 bythe end effector 82 that includes the load detection device of FIG. 6.The high flow/low vacuum source is initially applied. Upon engaging theobject 170, the system notes the position of the detection device andthe level of flow (F₂) within the end effector as well as the vacuumpressure (P₂) and load (W₂) as shown in FIG. 12A. Once the object 170 islifted (FIG. 12B), the system notes the change in the amount of flow(ΔF₂). As noted above, in this example, the object 170 is heavy (ΔW₂),presenting a higher load. The system will evaluate the load incombination with the flow (F₂) and pressure (P₂) as well as the changein flow (ΔF₂) and change in pressure (ΔP₂) to assess the grasp of theobject. The system may automatically switch to the high vacuum, low flowvacuum source as discussed above.

The system may also detect whether a load is not sufficiently balanced.FIGS. 13A and 13B show an object 180 being lifted from a surface 182 bythe end effector 82 that includes the load detection device of FIG. 6.The high flow/low vacuum source is initially applied. Upon engaging theobject 180, the system notes the position of the detection device andthe level of flow (F₃) within the end effector as well as the vacuumpressure (P₃) and load (W₃) as shown in FIG. 13A. Once the object 180 islifted (FIG. 13B), the system notes the change in the amount of flow(ΔF₃). In this example, the object 180 presents a non-balanced load(ΔW₃). The system will evaluate the load in combination with the flow(F₃) and pressure (P₃) as well as the change in flow (ΔF₃) and change inpressure (ΔP₃) to assess the grasp of the object. The system mayautomatically switch to the high vacuum, low flow vacuum source asdiscussed above. In each of the examples of FIGS. 11A-13B, any of vacuumpressure sensors, flow sensors, weight and balance detections may beemployed to monitor the status of the end effector and the load, and theswitching may occur automatically, or by analysis of the above values.

In accordance with certain embodiments, the system may switch between ahigh vacuum, low flow source and a low vacuum high flow source dependingon input from the sensor 84. For example, if an object is engaged suchthat the bellows is substantially moved in either directions B or C,then the system may elect to maintain the high vacuum, low flow source,or may elect to return the object without moving the object.

As discussed above, during low vacuum/high flow use, a specialized endeffector may be used that provides improved grasping of long narrowobjects. Certain grippers that are designed for high flow use to acquireand hold an object generally require large apertures in order to obtainan air flow rate that is high enough to be useful for objectacquisition. One drawback of some such grippers in certain applications,is that the object to be acquired may be small, not so small that eachof its dimensions is smaller than the high flow opening, but smallenough that certain of an object's dimensions is smaller than theopening. For example, long narrow objects such as pens, pencils etc., donot occlude enough of the high flow opening to generate sufficientnegative forces to hold the object securely.

In accordance with an embodiment, therefore, the system provides vacuumcontrol to an end effector of an articulated arm, where the systemincludes a vacuum source for providing a vacuum pressure at a flow rateto the end effector, and the end effector includes a cover that includesan opening that varies significantly in radius from a center of thecover. The opening may include finger openings that extend radially fromthe center of the opening. The opening may be generally star shaped orasterisk shaped. The cover may include compliant foam on a distal sideof the cover that engages an object to be grasped, and an air flowresistant material on a proximal side of the cover. The vacuum pressuremay be no more than about 25,000 Pascals below atmospheric, and the airflow rate may be at least about 100 cubic feet per minute to provide ahigh flow/low vacuum source. The cover may include an opening thatvaries significantly in radius from a center of the cover, and theopening may include finger openings that extend radially from the centerof the opening, and for example, may be generally star shaped orasterisk shaped.

Those skilled in the art will appreciate that numerous modifications andvariations may be made to the above disclosed embodiments withoutdeparting from the spirit and scope of the present invention.

What is claimed is:
 1. A system for providing dynamic vacuum control toan end effector of an articulated arm, said system comprising: (i) afirst air source for providing a positive air pressure; (ii) a secondair source for providing a negative air pressure; and (iii) amulti-stage ejector coupled at a first end thereof to the first airsource for receiving the positive air pressure and coupled at a secondopposite end thereof to the second air source tier receiving thenegative air pressure, wherein the first air source and the second airsource are thereby provided to the multi-stage ejector thatautomatically selects between a first vacuum source that uses the firstair source to provide a first vacuum pressure with a first maximum airflow rate and a second vacuum source that uses the second air source toprovide a second vacuum pressure with a second maximum air flow rateresponsive to a change in air pressure at an exit of the multi-stageejector without using an independently actuatable valve, wherein thefirst vacuum pressure is at least about 90,000 Pascals belowatmospheric, and said second vacuum pressure is no more than about50,000 Pascals below atmospheric.
 2. The system as claimed in claim 1,wherein said first maximum air flow rate is at most about 5 cubic feetper minute, and said second maximum air flow rate is at least about 100cubic feet per minute.
 3. The system as claimed in claim 1, wherein themulti-stage ejector includes a non-return valve.
 4. The system asclaimed in claim 1, wherein the system further includes at least onepressure sensor for providing a pressure sensor signal representative ofair pressure at the end effector.
 5. The system as claimed in claim 1,wherein the system further includes at least one flow sensor forproviding a flow sensor signal representative of air flow at the endeffector.
 6. The system as claimed in claim 1, wherein the systemfurther includes a release source for providing positive pressure at theend effector for ejecting an object from the end effector.
 7. A systemfor providing dynamic vacuum control to an end effector of anarticulated arm, said system comprising: (i) a first air source forproviding a positive air pressure; (ii) a second air source forproviding a negative air pressure; and (iii) a multi-stage ejectorcoupled at a first end thereof to the first air source for receiving thepositive air pressure and coupled at a second opposite end thereof tothe second air source for receiving the negative air pressure, whereinthe first air source and the second air source are thereby provided tothe multi-stage ejector that automatically selects between a firstvacuum source that uses the first air source to provide a first vacuumpressure with a first maximum air flow rate and a second vacuum sourcethat uses the second air source to provide a second vacuum pressure witha second maximum air flow rate responsive to a change in air pressure atan exit of the multi-stage ejector without using an independentlyactuatable valve, wherein the first maximum air flow rate is at mostabout 5 cubic feet per minute, and said second maximum air flow rate isat least about 100 cubic feet per minute.
 8. The system as claimed inclaim 7, wherein said first vacuum pressure is at least about 90,000Pascals below atmospheric, and said second vacuum pressure is no morethan about 50,000 Pascals below atmospheric.
 9. The system as claimed inclaim 7, wherein the multi-stage ejector includes a non-return valve.10. The system as claimed in claim 7, wherein the system furtherincludes at least one pressure sensor for providing a pressure sensorsignal representative of air pressure at the end effector.
 11. Thesystem as claimed in claim 7, wherein the system further includes atleast one flow sensor for providing a flow sensor signal representativeof air flow at the end effector.
 12. The system as claimed in claim 7,wherein the system further includes a release source for providingpositive pressure at the end effector for ejecting an object from theend effector.
 13. A method of providing a dynamic vacuum source for anend effector, said method comprising the steps of: (a) coupling a firstend of a multi-stage ejector to a first air source such that the firstend of the multi-stage ejector receives positive air pressure; (b)coupling a second opposite end of the multi-stage ejector to a secondair source such that the second end of the multi-stage ejector receivesnegative air pressure; (c) providing at the end effector a first vacuumfrom a first vacuum source that includes a compressor, said first vacuumproviding a first vacuum pressure and a first vacuum flow rate; and (d)switching the dynamic vacuum source to provide at the end effector asecond vacuum from a second vacuum source that includes a blower, saidsecond vacuum providing a second vacuum pressure and a second vacuumflow rate, said first vacuum pressure being at least about 90,000Pascals below atmospheric, and said second vacuum pressure being no morethan about 50,000 Pascals below atmospheric, wherein the first vacuumsource and the second vacuum source are provided by the multi-stageejector that employs a non-return valve as a selection mechanism toselect between the first vacuum source and the second vacuum source. 14.The method as claimed in claim 13, wherein said first vacuum flow rateis at most about 5 cubic feet per minute, and said second vacuum flowrate is at least about 100 cubic feet per minute.
 15. The method asclaimed in claim 13, wherein the step of switching the dynamic vacuumsource occurs automatically without any input commands.
 16. The methodas claimed in claim 13, wherein the method further includes the step ofconfirming, using an output of at least one pressure sensor, that thedynamic vacuum source has switched to the second vacuum pressure that ishigher than the first vacuum pressure.
 17. The method as claimed inclaim 13, wherein the method further includes the step of confirming,using an output of at least one flow sensor, that the dynamic vacuumsource has switched to the second vacuum flow rate that is greater thanthe first vacuum flow rate.
 18. The method as claimed in claim 13,wherein the method occurs during application of the end effector to anobject to be grasped.
 19. The method as claimed in claim 13, wherein themethod occurs during a process of lifting an object with the endeffector.
 20. The method as claimed in claim 13, wherein the methodoccurs during a process of moving an object with the end effector. 21.The method as claimed in claim 13, wherein the method further includesthe step of providing a positive air pressure to the end effector tourge an object from the end effector.
 22. A method of providing adynamic vacuum source for an end effector, said method comprising thesteps of: (a) coupling a first end of a multi-stage ejector to a firstair source such that the first end of the multi-stage ejector receivespositive air pressure; (b) coupling a second opposite end of themulti-stage ejector to a second air source such that the second end ofthe multi-stage ejector receives negative air pressure; (c) providing atthe end effector a first vacuum from a first vacuum source that includesa compressor, said first vacuum providing a first vacuum pressure and afirst vacuum flow rate; and (d) switching the dynamic vacuum source toprovide at the end effector a second vacuum from a second vacuum sourcethat includes a blower, said second vacuum providing a second vacuumpressure and a second vacuum flow rate, said first vacuum flow ratebeing at most about 5 cubic feet per minute, and said second vacuum flowrate being at least about 100 cubic feet per minute, wherein the firstvacuum source and the second vacuum source are provided by themulti-stage ejector that employs a non-return valve as a selectionmechanism to select between the first vacuum source and the secondvacuum source.
 23. The method as claimed in claim 22, wherein said firstvacuum pressure is at least about 90,000 Pascals below atmospheric, andsaid second vacuum pressure is no more than about 50,000 Pascals belowatmospheric.
 24. The method as claimed in claim 22, wherein the step ofswitching the dynamic vacuum source occurs automatically without anyinput commands.
 25. The method as claimed in claim 22, wherein themethod further includes the step of confirming, using an output of atleast one pressure sensor, that the dynamic vacuum source has switchedto the second vacuum pressure that is higher than the first vacuumpressure.
 26. The method as claimed in claim 22, wherein the methodfurther includes the step of confirming, using an output of at least oneflow sensor, that the dynamic vacuum source has switched to the secondvacuum flow rate that is greater than the first vacuum flow rate. 27.The method as claimed in claim 22, wherein the method occurs duringapplication of the end effector to an object to be grasped.
 28. Themethod as claimed in claim 22, wherein the method occurs during aprocess of lifting an object with the end effector.
 29. The method asclaimed in claim 22, wherein the method occurs during a process ofmoving an object with the end effector.
 30. The method as claimed inclaim 22, wherein the method further includes the step of providing apositive air pressure to the end effector to urge an object from the endeffector.